Improvement in furnaces for steam-boilers



i 2 She'ets-eSheet l. L. STEVENS.

Furn-aces'for Steam-Boilers. N0.l56,Q55 l Patented Nov. 17,1874.

UNITED STATEs PATENT OFFICE.

LEVI STEVENS, or WASHINGTON, DIsTEIcT 0E COLUMBIA.

IMPROVEMENT FURNACES FOR STEAM-BOILERS.

Specification forming part of Letters Patent No. 156,955, dated-November17, 1874; application filed October 28, 1873.

l To all'whom it may concern:

Beit known that I, LEVI STEVENS, of Washington, in the county ofWashington and District of Columbia, have invented certain Improvements,in Furnaces for Steam -Boilers, Sto., of which the following is aspecification:

My present invention relates to an improvement in furnaces for carryingout a process or` method heretofore invented by me for utilizing fuel,and for which method I filed an application for a patent July l5, 1873;and it consists in a novel construction and arrangement of the furnace,with superheaters, chambers, valves, tubes, &c., for mixing and feedingto the re the gases generated in the furnace with air and steam, for thepurpose of more eifectually utilizing the fuel and its products, ashereinafter more fully explained.

Figure lis a front elevation of my improved apparatus. Fig. 2 is atransverse section of the same on the line m of Fig. 3. Fig. 3 is alongitudinal section on the line y y of Fig. l. Fig. 4 is a View of aportion shown in detail.

This invention is intended for the same purpose as that for which I haveheretofore filed an application for a patent; and this mayproperly betermed an improvement thereon.

In constructing my present apparatus, I arrange the boiler A and thegrate G iu the usual manner, B representing the brick-work supportingthe same. Theiire-chamber I make wider than the grate, and locate asuperheater, S, at each side, in such a manner as to leave a narrowchamber or passage, lo, at each side between the superheater and thewalls, as shown in Fig. 2, these chambers having a perforated bottom, o,with a slide or damper, c, arranged to open or close the holes thereinat pleasure, the handle a of the slides c extending out through thefront wall, as shown in Figs. 1 and 3. Above the superheaters S aprojecting ledge or plate, t, is arranged, as shown in Fig. 2, todeflect the intlowin g gases and throw them directly over or onto theburning fuel on the grate. At the front, and outside of the wall, llocate, at each side of the grate, a vertical tube, C, the upper end ofwhich is provided with a sliding valve, d, or With any equivalentvalveor damper, for regulating the amount of air admitted to said tube.From this tube C I extend a pipe or tube, p, through the wall, with itsopen end terminating in vthe shoulder k, as shown in Fig. 3, so as totake gases from said chamber into the tube C. I have represented thetube p as terminating at the front end of the chamber la; but it may beextended the whole length thereof, or any portion of it, as may bedesired, in which case it will be provided with openings all along forthe gases to enter. At their lower ends the tubes C are provided withnozzles f, which enter through openings in the front wall, directlyunder the perforated bottoms o of the chambers la, as shown in Fig. 3. Apipe connects the boiler with the rear end of the superheater on eachside, and from their front ends the steam is conveyed by a pipe, h,whichpasses through the tube C, and has its end termina-ting in a nozzlearranged concentrically within the nozzle f, as shown in Fig. 3. It is,however, obvious that the pipe h, instead of extending through andoutside of the tube C, may extend down inside thereof, or be arranged inany other way, so that its end delivers the superheated steam throughthe nozzle f, so asao create a strong draft Within the tube C, andthereby draw air through its upper end, and also draw the gases fromwithin the furnace through the pipe p, and then deliver them, allmingled together, through the nozzle f into the furnace. rIhesuperheaters S, in this as in my former case, consist of a castironplate, having a zigzag passage extending through it from end to end, asshown in Fig. 3; and being arranged as represented in Fig. 2, it is notonly subjected to a high heat, but at the same time serves to form theinner wall of the chamber k.

The' apparatus, being thus constructed, operates as follows: Fuel beingapplied in the usual manner and the flre kindled, the holes o are closedby shoving in the slides c until the re is well started, after whichthey are opened,

the steam being admitted through the pipe l1J into the nozzle f. Thiscauses a strong draft through the tubes C, which draws the gases thrownoff by the burning fuel Within the iirechainber, through the pipes p,into the tubes G, where they are mingled with the air that is drawn inat the top of said tubes G, and both are injected together, with thesuperheated steam from the pipe h, into the spaces underneath thechambers k, from whence they pass up through the openings o into saidchambers k intothc ash-pit I?, and thence up through the grate G to there, thus supplying the necessary draft, and also the requisite amount ofoxygen to support combustion.

It Will be observed that the openings through which the nozzles f enterare larger than the nozzles, so that air is also drawn in through saidopenings more or less; and I propose to provide these .openings alsoWith registers or dampers, by which they can be opened or closedatpleasure, and thus, by these, together with the valves d in the tubesC, I am enabled to regulate at will the exact amount of air admitted tothe furnace. By these means I am enabled to produce so nearly a perfectcombustion of the fuel and its products that 'there is nop'erceptibleescape of smoke or gas fromthe furnace; and the fuel and its productsare so elfectually utilized that the same amount of steam can begenerated With a much less amount of fuel than has heretofore beenpracticable. v

Although this invention is particularly adapted to coal furnaces, it isobvious that it may be used with other fuel, and that is it applicableto other purposes as Well as to the generation of steam.

YHaving thus described my invention, what. Y' Y I claim isl. The tube G,provided with a valve, d, and connected With the fire-chamber by thetube p and nozzle f, in `combination With the steampipe h and chamber k,having a ledge, t, and perforated bottom o, regulated by a damper, 0,substantially as described, and for the purposes set forth.

2. rIhe arrangement of a gas-chamber, k, at the side of the grate, asdescribed.

LEVI STEVENS.

Witnesses:

J. MGKENNEY, WM. A. MCKENNEY.

